North Sea job losses?

Sustained low oil prices are also likely to cause "stress" on oil producing countries such as Norway, Russia, Venezuela, Scotland, Nigeria and Angola, he said.

"All these countries are really going to feel it," he said. "I think Scotland is going to be under some stress because of these low oil prices," he said.

BP has two large projects in the North Sea, including the Clair field, which have had £8bn investment over ten years, he said.

"Their economics are challenged now with these new prices," he added. "But we're in the North Sea for the long term. We have a large workforce in Scotland. There will be activities that we needed to pare back anyway."

The fallout from "difficulties in the US" - referring to the fatal explosion at the Deep Water Horizon oil rig - were affecting the business, he said.

Globally, BP and the rest of the energy industry were likely to see "significant workforce reductions," he added.

Oil price worries

Italian oil group Eni chief Mr Descalzi called for Opec to cut production.

He said: "Opec is like the central bank for oil which must give stability to the oil prices to be able to invest in a regular way."

Politicians, economists and industry leaders in Davos have been voicing their worries over the impact of lower prices.

We worry a little bit that the price signal may give disincentive for new energy types to develop, and could reduce investment in new non-fossil energyZhou Xiaochuan, People's Bank of China governor

Total and BHP Billiton both said on Wednesday that they would cut back on shale oil projects.

People's Bank of China governor Zhou Xiaochuan said low oil prices could slow down China's development of renewable energy projects.

He said: "We worry a little bit that the price signal may give disincentive for new energy types to develop and could reduce investment in new non-fossil energy,"

But he added that lower prices would be good for the economy and job creation, because China was dependent on imported oil and gas.

Opec's decision

Opec secretary general Abdullah al-Badri, also speaking at Davos, defended the group's decision not to cut output.

He said: "Everyone tells us to cut. But I want to ask you, do we produce at higher cost or lower costs?

"Let's produce the lower cost oil first and then produce the higher cost,"

"We will go back to normal very soon," he said.

Oil prices have sunk by almost 60% since June to below $50 a barrel because of a large supply glut.

The price slide accelerated after Opec decided in November not to cut production.